Conventionally in sanitary washing apparatuses that wash the private parts of the human bodies, there are provided heating devices that heat washing water used for washing to suitable temperatures in order not to give uncomfortable feelings to the human bodies. Examples of the sanitary washing apparatuses comprising such heating devices include hot water storage type sanitary washing apparatuses or instantaneous heating type sanitary washing apparatuses.
The hot water storage type sanitary washing apparatuses comprise hot water tanks previously storing predetermined amounts of washing water as well as heating the washing water to predetermined temperatures by heaters contained therein (see JP 2003-106669 A), and employ methods of feeding by pressure the washing water previously heated to the predetermined temperatures within the hot water tanks by tap water pressure or pumps or the like to spray the washing water from nozzles.
FIG. 39 is a schematic sectional view of a hot water tank unit in a conventional hot water storage type sanitary washing apparatus. The hot water tank unit in the hot water storage type sanitary washing apparatus is disclosed in JP 2002-322713 A.
As shown in FIG. 39, in the hot water tank unit, a thermistor 904 detects the temperature of washing water within a hot water tank 901 through a heat sensitive plate 903. A control circuit 905 instructs a hot water heater 902 provided within the hot water tank 901 to apply heat on the basis of the temperature detected by the thermistor 904.
Washing water previously stored in the hot water tank 901 can be heated and stored by the hot water tank unit. In the hot water tank unit, the temperature of washing water can be transmitted to the thermistor 904 irrespective of the posture of the hot water tank by providing the heat sensitive plate 903 extending from an upper part to a lower part of the hot water tank 901, whereby boil-dry of the hot water tank can be prevented.
In this hot water storage type sanitary washing apparatus, however, washing water within the hot water tank must previously continue to be maintained at a predetermined temperature until the private parts of the human body are washed. Therefore, power must be always supplied to the heating device so that power consumption is increased. When a plurality of persons continuously wash their private parts and previously use washing water whose amount is not less than the amount of the washing water heated to the predetermined temperature within the hot water tank, the temperature of the washing water within the hot water tank is lowered to not more than the predetermined temperature, giving the human bodies uncomfortable feelings.
On the other hand, the instantaneous heating type sanitary washing apparatuses employ methods of instantaneously heating washing water to predetermined temperatures by heating devices superior in temperature rise speed and feeding by pressure washing water utilizing tap water pressures or using pumps or the like to spray the washing water from nozzles when they wash the private parts of the human bodies.
Therefore, power need not be always supplied to the heating device so that power consumption is small. Even when a plurality of persons continuously wash their private parts and previously use washing water whose amount is not less than the amount of the washing water heated to the predetermined temperature within the hot water tank, the temperature of the washing water within the hot water tank is not lowered to not more than the predetermined temperature, not to give the human bodies uncomfortable feelings.
Heating devices having both the respective configurations of the hot water storage type sanitary washing apparatuses and the instantaneous heating devices have been developed. The heating device having both the respective configurations of the hot water storage type sanitary washing apparatus and the instantaneous heating device is disclosed in JP 2003-106669 A.
FIG. 40 is a schematic view of a conventional heating device having both the respective configurations of a hot water storage type sanitary washing apparatus and an instantaneous heating device.
As shown in FIG. 40, washing water is stored in a hot water tank 982 from an introduction port 980. A communication pipe 983 is provided within the hot water tank 980, so that washing water flows to a heating chamber 984 provided within the hot water tank 980 through the communication pipe 983. A cylindrical heater 986 is provided within the heating chamber 984, so that washing water flows to a washing nozzle 987 while being heated by the cylindrical heater 986. Consequently, hot water is sprayed from the washing nozzle 987.
In this heating device, the heating chamber 984 is provided within the hot water tank 980, so that the washing water within the hot water tank 980 is previously heated to a predetermined temperature. The washing water is heated again by the heater 986 before being sprayed from the washing nozzle 987. Thus, power can be reduced, and washing water suitably heated can be sprayed.
However, the heating device is difficult to miniaturize.
A ceramic heater is generally used as the heating device in the sanitary washing apparatus. The ceramic heater is disclosed in JP 10-160249 A.
FIG. 41 is a perspective view showing an example of a conventional ceramic heater.
As shown in FIG. 41, a ceramic heater 952 is provided so as to divide a tank 954 into two parts. The ceramic heater 952 is provided with a plurality of projection plates 953 so that a flow path snaked along the ceramic heater 952 is formed. Thus, it is possible to realize a hot water device having high heat exchange efficiency and superior in control response.
However, the ceramic heater is difficult to miniaturize.
A heating device that can be miniaturized, as compared with the ceramic heater, has been developed. The heating device is disclosed in JP 2001-279786 A.
FIG. 42 is a schematic sectional view of a conventional heating device.
As shown in FIG. 42, the heating device has a double pipe structure comprising a cylindrical base material pipe 961 and an outer cylinder 962. A heater 963 is provided outside the base material pipe 961. A helical core 965 is inserted into the base material pipe 961. Washing water is heated by the heater 963 while flowing between the helical core 965 and the base material pipe 961. As a result, washing water suitably heated by a small-sized heating device can be supplied In the heating device, however, heat from the heater 963 is radiated toward the outside of the base material pipe 961, so that heat exchange efficiency is not high. Since the helical core 965 is provided inside the heater 963, there is such a limitation that the helical core 965 must be formed of a thermally solid material.
In recent years, hot water has been put in a washing tub to do washing even in a clothes washing apparatus. In the conventional clothes washing apparatus, two water supply valves are disposed. One of the water supply valves is connected to a water facet as a water supply-side water supply valve, and the other water supply valve is connected to a water heater as a hot water supply-side water supply valve. In the conventional clothes washing apparatus, there are states where the temperature of hot water greatly varies depending on the capability of the water heater, the water temperature of tap water, and so on, and the temperature of hot water during hot water supply is not stabilized. As a result, when the water pressure is reduced so that the temperature of hot water is too raised, clothes may be damaged by heat. Therefore, a clothes washing apparatus capable of stably supplying hot water having a set temperature even if the temperature of the hot water in a water heater or the temperature of tap water varies is disclosed in JP 5-161781 A.
FIG. 43 is a schematic sectional view of a conventional clothes washing apparatus.
As shown in FIG. 43, the clothes washing apparatus is provided with a tap water-side water supply valve 984 for supplying washing water to a washing tub 981 from a water facet and a hot water supply-side water supply valve 985 for supplying washing water as hot water to the washing tub 981 from a water heater.
The clothes washing apparatus is provided with a thermistor 983 for detecting the water temperature within the washing tub 981, and a heater 982 for adjusting the water temperature within the washing tub 981 is provided below the washing tub 981.
When the temperature of hot water within the washing tub 981 is lower than a desired temperature, therefore, it is possible to adjust the temperature of the hot water by the heater 982 or supply hot water from the hot water supply-side water supply valve 985. When the temperature of hot water within the washing tub 981 is higher than a desired temperature, it is possible to supply water from the tap water-side water supply valve 984. As a result, the water temperature within the washing tub 981 can be changed to a predetermined temperature.
In the clothes washing apparatus, however, it takes a long time to boil water by the heater 982, so that a washing time period is lengthened. As a result, the washing performance of the clothes washing apparatus is reduced.